1. Field of the Invention
This invention is to do with securing loads on vehicles.
2. Description of the Related Art
The invention is particularly but not exclusively applicable to delivery of construction equipment or other plant to site by truck. In such usage it is clearly essential that the load be secured to the truck, and this is conventionally done by means of tackle comprising a plurality of straps or chains connected to a load platform or other part of the truck and tensioned over the load. Unfortunately such securing arrangements fail from time to time, and accidents occur, most dangerously when a load falls from a truck moving at speed along a road.
There are two main reasons for failures of the securing arrangements. First, the tackle may not be tensioned to the correct level when the truck is being loaded, before it moves off. Regulations generally require straps and other tethers to carry tags showing breaking strength and safe working load, but even where these figures are known operators may not have a ready means of adjusting the tension accordingly; and if one tether of a plurality is incorrectly adjusted it may adversely affect others. Second, a tether may break or otherwise become loose while the truck is in transit with its load, and heretofore in-transit failures of this kind have not been readily noticed by the driver, or indeed by other road users, to provide an opportunity for corrective action.
U.S. Pat. No. 5,295,664 (Kämper), which concerns a winch controlled in response to a tension sensor to keep lashing straps taut during transport, refers to previously known tension measuring aids integrated in the tensioned strap to indicate tension to the operator during the tensioning process, but notes that ‘a drop of tension occurring during transport, for instance due to settling of the load, generally remains unnoticed by the operator.’
It is an object of the present invention to enable tension in the tackle to be monitored.